Cisco Systems PRP-1/R= User Manual

When two PRPs are installed in a Cisco 12000 Series Router, one PRP is the 
active PRP and the other is a backup, or standby, PRP. If the active PRP fails or is 
removed from the system, the standby PRP detects the failure and initiates a 
switchover. During a switchover, the standby PRP assumes control of the router, 
connects with the network interfaces, and activates the local network management 
interface and system console.

If your system includes redundant PRPs, both PRPs should be of the same type 
(PRP-1 or PRP-2) and have the same memory size. Redundancy is not supported 
when using a Gigabit Route Processor (GRP) and a PRP in the same chassis. 
Cisco strongly recommends that you avoid configuring your router using mixed 
route processor cards. Refer to the Route Processor Redundancy Plus for the 
Cisco 12000 Series Internet Router publication for more information on 
redundancy. 

For software configuration information, refer to the Cisco IOS software 
configuration and command reference publications for the installed Cisco IOS 
Release. Also refer to the Cisco IOS software release notes for additional 
information.

The PRP is compatible with Cisco IOS Release 12.0(22)S or later.

The show version and show hardware commands display the current hardware 
configuration of the router, including the system software version that is currently 
loaded and running. For complete descriptions of show commands, refer to the 
Cisco IOS Configuration Fundamentals Configuration Guide and the Cisco IOS 
Configuration Fundamentals Command Reference.